Gas-distributing system



Apr. 10, 1923.

E. A. MITCHELL GAS DISTRIBUTING SYSTEM Filed July 26, 1922 5 sheets-sheef l Apr. 10, 1923. 1,451,303 4 a E. A. MITCHELL 1 GAS DISTRIBUTING SYSTEM Filed July 26, 1922 s shee bssheet '2 @953V 0 r 1 T r Z 7 g E. A. MITCHELL GAS DISTRIBUTING SYSTEM 5 sheets-sheet 3 Fi led July 26, 1922 9 9&0 6) 0 i .l L.

m 1 5 a: /f' V l t E C 1 7 1 I g I I] I i i I l Patented Apr. 10, 1923.

EDWARD ALBERT MITCHELL, or LONDON; ENGLAND.

' GAS-DISTRIBUTING SYSTEM.

Application filed July 26,

in or Relating to Gas-Distributing Systems (for which I have filed an application in Great Britain dated Mar. 94,1921, #9,160

and an application in France dated Mar. 28, 1922, #157,3i3), of which the following is a specification.

This invention relates to gas distributing systems, wherein combustible gas is supplied under high pressure to a pipe line by which it is to be conducted from the generating station to a distributing station at a considerable distance there-from.

In such cases, it is usual to compress the gas at the generating station to a high pressure and to conduct it through a pipe of comparatively small bore to the distributing station. With such an arrangement, the terminal pressure is very much lower than the initial pressure. For instance, assuming the generating and distributing stations are many miles apart, say twenty miles, the gas, owing to the friction of the pipe line, may fall from an initial pressure of say for example fifty pounds to the: square inch to a terminal pressure of say for example ten pou'ndsto the square inch. If it be desired to conduct part of the gas from the distributing station to another distributing station at a considerable distance from the first one, it will be necessary, in order not to increase the initial pressure of the gas, or to use a pipe line of larger bore, to instal at the first distribut ing station, means for raising or boosting the pressure of the gas received at that station, in order that it may be transmitted to the second distributing station at a pressure suitable for use.

Now the present invention has for its object to enable this result to be attained in a simple and economical manner.

For this purpose, there. are provided for use at the first distributing station, means whereby part of the gas received at low pressure at that distributing station can be raised in pressure by the: remainder of the low pressure gas, or part thereof, and transmitted through a second pipe line to a second distributing station. The low pressure gas thus utilized asmotive fluid for compressing the remaining low pressure gas to a suitably high pressure, can, after such use, be dis- 1922. Serial No. 577,673.

tributed at a suitably further reduced pressure, say for exampleto three fourths of a pound to the square inch, to gas users in the district or zone supplied from the first distributing station.

be provided for use at the first distributing station, a gas compressing plant comprising two cylinders, hereinafter called for dis tinction a. and b, of different diametersand each provided with a piston or plunger and with valve controlled inlet and outlet pipes or branches. Cylinder a is of less diameter than cylinder Z), and its piston or plunger is operatedfrom the piston or plunger of cylinder Z). i v

At the distributing station there are also provided gas reservoirs or containers. The low pressure gas inlet of each cylinder'is adapted to be connected through its valve controlled pipe to the pipe line coming from the generating station, or to a gasreservoir or container into which gas is deliveredfrom the said pipe line. The gas outlet of cylinder at is connected through its valve controlled pipe to a compressed gas reservoir from which extends a second pipe line to'a second distributing station. The gas outlet from cylinder 2) is connected through its valve controlled pipe to a low pressure gas distributing reservoir from which gas at lower pres: sure than that delivered by the first pipe line can be distributed to gas users in the district orzonew served by the distributing station.

The arrangement is such that assuming the two pistons are at the end of their return strokes, the gas inlet and outlet valves of cylinder a are respectively open and closed so that such cylinder will havebeen charged with gas from the first pipe line,

For carrying out the invention there may or the reservoir connected thereto, and that the gas inlet and outlet valves of cylinder 6 are respectively closed and open, then upon the outlet valve of cylinder 1) being closed and the inlet'valve of that cylinder opened and the inlet valve of cylinder a being closed and the outlet valve of that cylinder opened, low pressuregas willflow into cylinder 6 and cause its piston to make its working stroke. The piston of cylinder (1 will thereby be caused to travel andco'mpress the low pressure gas therein to affres h initial high pressure and force it into the high pressure gas reservoir whence it passes-to the'sec 0nd pipe line, Upon the gas inlet and out- I at let valves of cylinder 5 being respectively closed and opened and the inlet and outlet valves of cylinder a being respectively opened and closed, gas at low pressure will again pass from the first pipe line, or associated gas reservoir, into cylinder (1 and cause the pistons or plungers of both cylinders to make their return strokes and displace the spent gas from cylinder 7) through the gas outlet from that cylinder into the low pressure reservoir associated with that cylinder and wherein the pressure is less than the terminal pressure of the first pipe line. From the last mentioned reservoir, gas can be supplied to the district or Zone consumers ata suitably lower pressure than the pipe line terminal pressure. The terminal pressure may, for example, be of the order of ten pounds to the square inch and the district or zone pressure may be say three fourths of a pound to the square inch. The valves can then be reversed so as to cause the piston in cylinder 7) to again make its working stroke to compress and force a further quantity of gas from cylinder a into the high pressure gas reservoir. The valves of cylinder I) may suitably be interconnect ed to enable them to be worked at the required times and in the required manner from"suitable operating means.

In order that the pistons or plungers of the two cylinders a and b may work automatically and independently of any external operating means requiring to be independently driven, there may be associated with the piston of cylinder 6, means for operating or controlling, at the required times, the gas inlet valve of cylinder 6 and also, the gas outlet valve of cylinder 6. Such valve operating means may be constituted by cam, lever or equivalent mechanism. Or the inlet and outlet valves of cylinder 6 may be interconnected and positively operated, and the inlet and outlet valves of cylinder 0. be

automatic non-return valves.

In the accompanying illustrative drawings. Fig. 1 shows partly in vertical. section on the line I I of Fig. 3 and partly in side elevation, Fig. 2 in elevation at right angles to Fig. '1 and Fig. 3 in plan, one construc tion of gas compressing plant according to the invention, arranged at the first distributing station. Fig. 4 shows partly in side elevation and partly in vertical section; Fig. 5 partly in vertical section on the line VV of Fig. 6 and partly in side elevation and Fig. 6 in plan, a modified arrangement.

' In the example shown in Figs. 1, 2, and 3, a and b are two cylinders arranged one below the other, I) being of larger diameter than a, and fitted with a piston 0 connected to a plunger 03 of smaller diameter arranged to work in cylinder a. Cylinder b is, provided-with a low pressure gas inlet at e and with a gas outlet 7, and cylinder a is provided with a low pressure as inlet 9 and with a high pressure gas out et h. The gas inlet 6 of cylinder 6 is connected by a pipe 71 21 provided with an inlet valve 70, to a low pressure gas supply pipe Z connected either directly, or, as shown, indirectly through a reservoir Z to the pipe line Z coming from a gas generating station at a distance. The pipe 2' may also, if desired, be provided with a spring controlled nonreturnvalve The gas outlet is connected by a pipe m, provided with an exhaust outlet valve n, to an exhaust pipe 0 connect ed to a low pressure gas reservoiro from which consumers served from the said distributing station can receive a supply of gas at lower pressure than that supplied to the gas compressing plant from the pipe line Z The low pressure gas inlet 9 of cylinder a is connected to the low pressure gas supply pipe Z by apipe 79, provided with a spring controlled non-return valve .9. The high pressure gas outlet h is connected by a pipe t, provided with a spring controlled nonreturn valve u, either directly, or as shown, indirectly through a high pressure gas reservoir 25 to a second pipe line t extending to another distributing station at a distance from the first one. The gas inlet valve is and gas outlet valve n are arranged to be opened and closed bymovement derived from the piston o. In the example now being described, the valve is has a stem provided with a cross pin 7: extending into a slot e in the upper end of a rod 1;, the lower end of the rod being provided with a rectangular frame o within which Works a cam 00. This cam is fixed on a spindle y to which is fixed a toothed wheel 1 in gear with a vertical rack 2 connected to the piston c. The valve rod 1) isprovided with a wedge shape projection 3 against which acts a spring bolt 4:. The gas outlet or exhaust valve 12 has a stem 5 which is interconnected with the valve rod o by a lever 6 pivoted at 7 The bottom of cylinder Z is in this example, open to the external atmosphere.

The operation of the gas compressing plant ust described will generally be understood from what has already been stated but may be further briefly described as follows :--lVith the parts in the position shown in Figs. 1 and 2, low pressure gas from the pipe line Z will have been admitted to the top of the cylinder 6 through the pipes Z, 71 i and open inlet valve 70 and port 6 and caused the piston c in that cylinder to have madeits downstroke and caused the plunger (:1 to have made its downstroke and compressed the gas previously admitted to the cylinder at from the low pressure gas supply pipe Z, through the pipe 2), non-return valve 8 and gas inlet 9, and forced it through the outlet valve 11. and pipe 25' to the second pipe line If", either directly, or through the low is; l

pressure gas reservoir t ifthis reservoir be used. During the descent of the piston and plunger. the rack 2 will have rotated the cam 03 and, through the frame 3/ will have moved the valve rod '0 downward independently of the valve stem 70 and caused the wedge sha Jed oro'ection 3 to store energy n the spring associated with; the bolt 4i until the-centre of the said projection 23 comes just below the centre of pressure of the spring bolt. whereupon the bolt will act to suddenly. move the valve rod downward to a sufficient extent to close the gas inlet valve 7) and simultaneously open the outlet or exhaust valve n by the action of the lever 6 and place the cylinder Z) in communication with the low pressure gas outlet pipe 0. As the gas pressure above the piston 0 will new fall consderably below the pressure in the low pressure gas supply pipe Z, gas from that pipe will flow through the pipe p, past the non-return inlet valve 8 and through the gas inlet 9 into the lower end of cylinder and cause the plunger (Z- and piston 0 to make-their upward or return stroke, the spent gas above piston a being thereby displaced through the outlet flexhaust pipe on, open exhaust valve a and exhaust pipe 0 intothe low pressure gas reservoir'oh From this reservoir, the pressure within which will be much lower than that of the low pressure gas delivered into cylinder 7) from pipe Z, gas can be delivered" to consumers in the district or zone to be served by the distr buting station. When the piston c and plunger d nearly reach-the end of their u stroke, the rack 2 will have rotated the cam into a position in which it will. have raised the valve rod 1) independently of the stem 1: of the inlet valve Z" and moved the 1 rentre of the wedge shaped projection 3 just above the centre of pres sure of the spring bolt 4, whereupon the bolt will react, under the energy previously stored in its spring, and rapidly raise the valve rod to a further extent and open, the gas inlet valve 7c and closethe gas, exhaust valve Low pressure gas will then again enter the upper end of the cylinder 7? and cause the piston c and plunger Z to make their next downstroke and compress the in cylinder a throughthe gas outlet it, past the nonreturn valve 25- and through the out let pipe t to the second pipe line 25 As will be read ly understood the above described operations will take place automatically.

In the modified arrangement shown in Figs. 4, 5 and 6. the piston c of the larger cylinder 7) is provided with a tubular plunger (Z that works in a gas tight manner through an opening in the'bottom cover 6 of the cylinder so that. when p ston c and plunger (Z rise, an annular gas spacewill be formed at a between the cylinder 6, the

0 the pin being depressec The gas inlet valve is of cylinder b is this case arranged to 'be closedby the raising of'a rode which is connectedat its upper end,.as'by alever 9, to the at its lower end,by a leverlO, to a pin 11 projectinginto the smaller cylinder or space and" the valve closed by the piston just beforethe latter reaches the bottom of its stroke. The gas valve kl-is opened, when the piston nearly reaches the end of its upstroke, by causing the piston 0 to strike against a pin 12 connected to the said valve and projecting into exhaust valve 7% is opened and closed by similar rod, lever and pin mechanism 1), 9 10 11,'12 actuated by the piston 0 just before it completes xits downward and upward strokes respectively. Low pressure mit the said. smaller cylinder orgas space V (L to be -fi lled..with low pressure gas, such gas being compressed and forced through the outlet 7iv past the non-return valve u and through the pipe 6 to'the high pressure reservoir and second pipe line,..when the gas inlet valve 7% closed, in, a similar manner to that here nbet'ore described Figs, 1, 2 and'3.. Each valverod ano may be temporarily held in the position into which it is moved by the piston 0, by means of a spring stop 4- arranged to act against one or other side of a projection 3 on the rod. I

Valve v operating mechanism constructed and, operating; in the manner shown in and for pumped fluid and piston'nieans coop.-

valve, and

valve 11 is opened and the .gasoutlet with I reference to actuating fluid and a space the top of the cylinder 6. The gas outlet or i erating with said spaces havinga greater area exposed to fluid pressure in the space for actuating fluid and a smaller area eX- posed to fluid pressure in the space for pumped fluid, a valved inlet connection leading to said space for actuating fluid from the medium pressure reservoir, a valved outlet connection leading from the last mentioned space to the low pressure reservoir, a valved inlet connection leading to said space for pumped fluid from the medium pressure reservoir, and a valved outlet connection leading from the last mentioned space to the high pressure reservoir.

2. The combination, in a gas distributing system, with means for supplying a distant distributing station with gas under low pressure, of a low pressure reservoir at said station and means for filling said reservoir with gas of low pressure and simultaneously raising the pressure ot a part of the received at said station and transmitting it to another station; the latter means comprising cylinder mechanism having a gas receiving space of comparatively large area and a gas receiving space of smaller area, a fluic -pressure-actuated piston in said space of larger area and means associated therewith for com pressing gas in said space of smaller area, low pressure gas supply and exhaust pipes connecting said space of larger area with said source of supply and said low pressure reservoir respectively, inlet and outlet valves for controlling said supply and exhaust pipes respectively, low pressure gas supply and high pressure delivery pipes respectively, connected to said space of smaller area, and automate non-return inlet and outlet valves for controlling the two last mentioned pipes.

'8. A gas compressing plant comprising a. cylinder, a piston therein, gas inlet and outlet pipes connected to one end of said cylinder, inlet and outlet valves in the respective pipes, a cover fixed to the opposite end of said cylinder and provided with gas inlet and outlet ports, a cylindrical plunger connected to, co-axial with and '01 smaller diameter than said piston and extending in fluid tight manner through said cover, so that the outer annular portion of the piston between the cylinder wall and plunger forms a secondary and smaller piston and the annular space formed between the secondary piston and cylinder cover and the wall. of the cylinder and plunger, during the working of the combined pistons, forms a cylindrical chamber in which gas admitted thereto can be compressed by said secondary piston, means under the control of said combined pistons for opening and closing the said inlet and outlet valves, a gas inlet pipe connected to the inlet port in said cylinder cover, a valve controlling said inlet pipe, a compressed gas outlet pipe connected to the outlet port of said cylinder cover and a valve controlling said outlet pipe.

4. A gas compressing plant comprising a cylinder, a piston therein, gas inlet and outlet pipes connected to one end of said cylinder, inlet and outletvalves in the respective pipes, each having a stem extendinto said cylinder and into the path of said piston, a cover fixed to the opposite end of said cylinder and provided with inlet and outlet ports, a plunger coaXial with, connected to and of smallerdiameter than said piston and extending in a fluid tight manner through said cover, pins extending through said cover into the cylinder and into the path of said piston, rod and lover mechanism connecting each pin to one of the said valves, gas inlet and outlet pipes connected respectively to the gas inlet and outlet ports in said cover andautomatic non-return inlet and outlet valves in the last mentioned inlet and outlet pipes respectively.

, 5. In a gas distributing system of the kind herein referred to comprising apipe line, a gas compressing plant comprising a vertical cylinder, a supply pipe connected to said pipe line, a cylinder having gas inlet and outlet ports at one end, a gas inlet pipe connecting said gas supply pipe to said inlet port, a gas outlet pipe connected to said outlet port, gas inlet and outlet valves in said inlet and outlet pipes respectively, a cover secured to the opposite end of said cylinder and provided with gas inlet and outlet ports, a plunger coaxial with, connected to and of smaller diameter than said piston and extending in a fluid tight manner through said cover, means actuated by said piston for closing and open ing said. gas inlet valve when the piston is nearing the end of its downward and upward strokes respectively, means actuated by said piston for opening and closing said outlet valve when the piston is nearing the end of its downward and upward strokes respectively, a gas inlet pipe connecting said gas supply pipe to the gas inlet port in said cover, a compressed gas delivery pipe connected to the gas outlet pipe in said cover, and automatic non-return valves in the last mentioned gas inlet and outlet pipes.

Signed at American consul general, London, 14: day of July, 1922;

EDl/VARD ALBERT MITCHELL, 

